Structure of fast ion conducting AgI–As2Se3 glasses

High-energy X-ray diffraction, neutron diffraction and extended X-ray absorption fine structure experiments have been carried out for (AgI)x(As2Se3)1−x glasses. The addition of a large amount of AgI does not significantly affect the short-range ordering of the host network matrix, that is, As(Se1/2)3 pyramidal units remain essentially intact on introducing AgI. The interatomic distance of Ag–I pairs is similar to the case of crystalline AgI. However, the coordination number of Ag–I pairs in the present glasses seems to be somewhat smaller than that in the crystalline AgI, suggesting a heavy distortion of tetrahedral coordinates of AgI units or structural disorder of the I–I sub cages in the glass state.